Dipole frame options?

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These are the two configurations I have come up with so far to keep height down a bit. Of the two, is one much better than the other? I would assume the W shaped baffle will make a more even front and rear wave since the drivers are equal and opposite in direction. I do have some conserns using angles smaller than 45 degrees, but it is imperative to keep the height down a bit.

P.S. ignore the tweeters. I'm still playing with the top baffle configuration.

Ideas/thoughts?

Thanks,

Blair
 

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These are the two configurations I have come up with so far to keep height down a bit. Of the two, is one much better than the other? I would assume the W shaped baffle will make a more even front and rear wave since the drivers are equal and opposite in direction. I do have some conserns using angles smaller than 45 degrees, but it is imperative to keep the height down a bit.

P.S. ignore the tweeters. I'm still playing with the top baffle configuration.

Ideas/thoughts?

Thanks,

Blair

Hi Blair,

If the drawing is approx. to scale, I assume the woofers are 10's? What high do plan to cross them at? Are you concerned about floor reflection due to the driver's angle?
 
Hi Blair,

If the drawing is approx. to scale, I assume the woofers are 10's? What high do plan to cross them at? Are you concerned about floor reflection due to the driver's angle?


Driver selection is an important part. You can get respectible bass output from only one or two 10" drivers, if they can move enough air and have a fairly high QTS. Having only 2 woofers vertically mounted should put the mid/tweeter at an appropriate (ear) height.

I have found, for example, that my dipole with 1 X 10" driver (Qts .62, xmax 13mm, Fs 33Hz) has better quality and produces better quantity of low frequency sound than a friend's dipole with a 15" pro audio driver. My baffle is also less than half the size. The only advantage he may have is effeciency, but watts are fairly cheap these days, especially in the LF's where a class D amp can be used easily on the cheap.
 
If you are going to use a separate amp or use an active X-over you won't need four woofers, your mid/tweet will give out before two 10" will.
You did not draw a dipole (as it looks like there is a back side in your drawings). I assume you ment a modified W frame open baffle?
I've made several sets of open baffles, two with 15 inch Emminence alpha's and one with Goldwood 18inch. all using Audio Nirvana 10" or 12".
They all used a separate plate amp (The quietest-no ground loop was the M & K plate amp).
Two 10" would give the same size as one 15", and I can tell you that for balanced sound, I had the plate amp set about halfway. Playing music at just under 100dB, I could crank the plate amp higher!,
SO, in my opinion, unless you like the look, there isn't much reason to use more than 2 ten inchers (Unless you want a passive crossover and are using one amp),
If so, spread the angle out as much as possible. If your using a Full range driver, don't worry if the center is a little high, as this may help mitigate the rising high end any way.
Hope this helps,
Paul
 
Thanks guys!

This all makes sense to me. I am looking at a 9mm xmax driver with a relatively high Qts. 1.35.

A pair should do well, but three or four would put my mind at ease much better as far as limitations. Then again, 30" is not too bad to place the mid and tweeters. Mu current speakers have the center of the mid at about 43".

I would be using separate 100w plate amps in each speaker with a shelving circuit.

Blair
 
I've made several sets of open baffles, two with 15 inch Emminence alpha's and one with Goldwood 18inch. all using Audio Nirvana 10" or 12".
They all used a separate plate amp (The quietest-no ground loop was the M & K plate amp).
Two 10" would give the same size as one 15", and I can tell you that for balanced sound, I had the plate amp set about halfway. Playing music at just under 100dB, I could crank the plate amp higher!,

Do you have pictures you can either send me or link to? How wide are your baffles on your 10" drivers?

Oh, and yes, this is more of a modded W frame.

Thank you!

Blair
 
Do you have pictures you can either send me or link to? How wide are your baffles on your 10" drivers?

Oh, and yes, this is more of a modded W frame.

Thank you!

Blair


Blair,

My project is online below. I'm listening to them right now and the LF output is quite impressive. My baffles are only about 12" wide, but I do comp the low frequencies by as much as 6dB with my DEQ2496 in the 40Hz to 100Hz region, then cut frequencies around 3dB from 125Hz to 250Hz. Mostly flat up into the upper registers, then slight boost again from about 8Khz on up. This works well for me in my particular room and achieves the house curve I prefer.

http://home.comcast.net/~cunundrum

Ed
 
I wanted my H frame woofer cab to be as small as possible so it is about 3 1/2 inchis wider than the speaker on the sides a little more than that top and bottom. If you go wider you may get slightly higher efficiency. If you go deeper, my may get a slight rise in freq response at the crossover. Mine follow Martin J Kings article (easy to find google quarter wave loudspeaker design)
Hope this helps (and that the pictures worked!)
Paul
 

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When I built the same thing with 18" I used the goldwood speakers.They were for my brother. He is a drummer and is a bass *****. The 15" were for a friend of mine and another for my daughter they are the Alpha eminence.
I never side by side compared them. They both sounded great. I used a shelving filter on the audio nirvana's on all of them. Took a little time adjusting the resistor value. But with a plate amp, it was easy to integrate (fairly well) both kinds of speakers with the full range unit.
Even with one 15" unit, and one plate amp per speaker I had no trouble getting enough bass. In fact full up on the volume of my main amp with plate amp volume set half way for best integration with the full ranger, I could turn the plate amp up further, and the 15" still got louder and louder!
I tried the parts express plate amp and had a devil of a time with low level hum.
On the other two units I used the M & K unit. absolutely quiet.
If you read about the Parts express unit. You'll find lots of people trying to find out how to get rid of the hum.
Paul
 
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